Store Kubernetes Cluster Credentials in Jenkins and use in declarative pipeline - jenkins

Question

I am trying to deploy k8s cluster using Helm 3 and jenkins. Jenkins and k8s running on different servers.I merged the kubeconfig files and I had all information in one config file ./kube directory. I would like to deploy my app to the related environment and namespace according to the GIT_BRANCH value. I have two question for below script.
1.What is the best way should I store k8s cluster credentials and will use in pipeline. I saw some plugins such as Kubernetes CLI but I can not be sure whether it will cover my requirement. If I use this plugin, should I store k8s file in to Jenkins machine manually or this plugin already handle this with uploading config file.
2.Should I change anything in below script to follow best practices?
stage('Deploy to dev'){
script{
steps{
if(env.GIT_BRANCH.contains("dev")){
def namespace="dev"
def ENV="development"
withCredentials([file(credentialsId: ...)]) {
// change context with related namespace
sh "kubectl config set-context $(kubectl config current-context) --namespace=${namespace}"
//Deploy with Helm
echo "Deploying"
sh "helm upgrade --install road-dashboard -f values.${ENV}.yaml --set tag=$TAG --namespace ${namespace}"
}
}
}
}
stage('Deploy to Test'){
script{
steps{
if(env.GIT_BRANCH.contains("test")){
def namespace="test"
def ENV="test"
withCredentials([file(credentialsId: ...)]) {
// change context with related namespace
sh "kubectl config set-context $(kubectl config current-context) --namespace=${namespace}"
//Deploy with Helm
echo "Deploying"
sh "helm upgrade --install road-dashboard -f values.${ENV}.yaml --set tag=$TAG --namespace ${namespace}"
}
}
}
}
}
stage ('Deploy to Production'){
when {
anyOf{
environment name: 'DEPLOY_TO_PROD' , value: 'true'
}
}
steps{
script{
DEPLOY_PROD = false
def namespace = "production"
withCredentials([file(credentialsId: 'kube-config', variable: 'kubecfg')]){
//Change context with related namespace
sh "kubectl config set-context $(kubectl config current-context) --namespace=${namespace}"
//Deploy with Helm
echo "Deploying to production"
sh "helm upgrade --install road-dashboard -f values.${ENV}.yaml --set tag=$TAG --namespace ${namespace}"
}
}
}
}

Answer 1

I have never tried this, but in theory the credentials variable is available as environment variable. Try to use KUBECONFIG as a variable name
withCredentials([file(credentialsId: 'secret', variable: 'KUBECONFIG')]) {
// change context with related namespace
sh "kubectl config set-context $(kubectl config current-context) --namespace=${namespace}"
//Deploy with Helm
echo "Deploying"
sh "helm upgrade --install road-dashboard -f values.${ENV}.yaml --set tag=$TAG --namespace ${namespace}"
}

Answer 2

A workaround that worked for me:
withCredentials([file(credentialsId: 'k8s-dk-staging', variable: 'KUBECRED')]) {
sh 'cat $KUBECRED > ~/.kube/config'
sh './deploy-app.sh'
}
I don't like to do that, ideally I would like use KUBECONFIG but for now this is that works for me.